Effect of boundary conditions on the kinetics of helium release from structural materials

2015 ◽  
Vol 116 (11) ◽  
pp. 1103-1107 ◽  
Author(s):  
A. G. Zaluzhnyi
Keyword(s):  
Boundary Conditions ◽  
Structural Materials ◽  
Kinetics Of

Phase Formation and Kinetic Processes in Silicide Growth.

1983 ◽  
Vol 25 ◽  
Author(s):  
G. Ottaviani
Keyword(s):  
Boundary Conditions ◽  
Phase Formation ◽  
Growth Kinetics ◽  
Metal Layer ◽  
Silicide Phase ◽  
Reaction Products ◽  
Silicon Structures ◽  
Silicide Growth ◽  
Kinetic Processes ◽  
Kinetics Of

ABSTRACTTwenty years of research have now been devoted to investigating reaction products obtained by annealing metal-layer/silicon structures. A wide variety of cases have been analyzsed and a considerable amount of data has been produced. Despite the vast amount of information available, several aspects concerning phase formation and kinetic processes are not yet well established. The purpose of this paper is to investigate the mechanisms of phase formation and to show the importance of kinetic factors in the appearance of various compounds. Results will be shown for a single metal layer deposited on silicon, for bilayers. and for alloys. Depending upon the starting structure, metal-rich or silicon-rich silicides can be formed. Moreover, by modifying the boundary conditions, it is possible to change the growth kinetics of the silicide phase that forms.

scholarly journals Numerical analysis of heat, air, and moisture transfers in a wooden building material

2017 ◽  
Vol 21 (2) ◽  
pp. 785-795 ◽  
Author(s):  
Faiza Mnasri ◽  
Kamilia Abahri ◽  
Ganaoui El ◽  
Rachid Bennacer ◽  
Slimane Gabsi
Keyword(s):  
Numerical Analysis ◽  
Moisture Content ◽  
Boundary Conditions ◽  
Thermal Diffusion ◽  
Building Material ◽  
Macroscopic Model ◽  
Drying Process ◽  
Wood Panel ◽  
Hygrothermal Behavior ◽  
Kinetics Of

The present paper aims to predict the hygrothermal behavior of massive wood panel considered as bio-based building material. In this context, we developed a macroscopic model coupled no linear heat, air, and moisture transfers that incorporates simultaneously the effect of thermal diffusion and infiltration phenomenon on the building material. The model inputs parameters were evaluated experimentally according to the recognized standards of material?s characterization. Therefore, numerous series of hygrothermal calculation were carried out on the 1-D and 2-D configuration in order to assess the dimensionless effect on such wooden material. Two types of boundary conditions were considered and examined. The first are at the material scale of wood drying process. The second type of conditions is at the wall scale, where the conditions of the building ambiance are considered. Moreover, the model sensitivity to the driving potentials coupling and to the parameters variability was considered and examined. It has been found that the coupling in the model had a remarkable impact on both kinetics of temperature and moisture content.

scholarly journals Diffusion and the torsion parameter

1994 ◽  
Vol 35 (3) ◽  
pp. 289-301 ◽  
Author(s):  
Alex McNabb ◽  
Grant Keady
Keyword(s):  
Boundary Conditions ◽  
Torsional Rigidity ◽  
Decay Rates ◽  
Dirichlet Boundary Conditions ◽  
First Eigenvalue ◽  
Diffusion In Solids ◽  
Immobile Phase ◽  
The Mean ◽  
Kinetics Of ◽  
General Linear Boundary Conditions

AbstractThe parameters describing the trapping kinetics of a linear model for diffusion, in solids involving a captured immobile phase of the diffusing entity, can be determined by measuring mean residence times for matter in the systems and evaluating the exponents for the final exponential decay rates of the diffusing entity from various shaped solids. The mean residence time for matter in a given region can be expressed in terms of a “torsion parameter” S which in the case of Dirichlet boundary conditions and cylindrical geometries, coincides with the torsional rigidity of the cylinder. The final decay rate is given by the first eigenvalue μ of a Helmholtz problem. Expressions and inequalities are derived for these parameters S and μ for general linear boundary conditions and for geometries relevant to diffusion experiments.

scholarly journals Kinetics of Reaction on a Single Catalytic Particle in a Fluidic Nanochannel

2019 ◽  
Vol 150 (6) ◽  
pp. 1749-1756 ◽  
Author(s):  
Vladimir P. Zhdanov
Keyword(s):  
Boundary Conditions ◽  
Flow Reactor ◽  
Plug Flow ◽  
Interesting Case ◽  
Dirichlet Boundary Conditions ◽  
Various Boundary Conditions ◽  
Catalytic Nanoparticles ◽  
Kinetics Of Reaction ◽  
Long Channel ◽  
Kinetics Of

Abstract One of the frontiers in heterogeneous catalysis is focused on reactions occurring on single catalytic nanoparticles. In this context, a reaction taking place on a single nanoparticle in a fluidic nanochannel is herein described by using the equation similar to that employed for a plug-flow reactor with dispersion. In the literature, one can find various boundary conditions for this equation. In the practically interesting case of a relatively long channel, the Dirichlet boundary conditions are shown to be valid. The corresponding analytical and numerical results illustrate the specifics of the profiles of the reactant concentration along the channel and the dependence of the reaction rate on the parameters. For comparison, the Danckwerts boundary conditions were used as well. Graphic Abstract

Effect of Silver Additions on the Ageing Behavior and Mechanical Properties of Mg-Al-Si-Sn-Sr Alloy

2007 ◽  
Vol 124-126 ◽  
pp. 1469-1472
Author(s):  
S.W. Lee ◽  
Byung Ho Kim ◽  
K.Y. Nam ◽  
Dae Hyun Song ◽  
Kyung Mok Cho
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Structural Materials ◽  
Damping Capacity ◽  
Low Density ◽  
Ag Addition ◽  
Silver Additions ◽  
Kinetics Of

Mg is one of the most promising structural materials for lightweight applications due to its low density, good castability and damping capacity. In this study, we investigated the effect of silver (Ag) addition on alloy ageing behavior and mechanical properties of Mg-Al-Si-Sn-Sr-Ag alloys with variation of Ag contents (0.1, 0.5, 1.0, 2.0wt%). The ageing kinetics of Ag added alloys was determined and affected by Ag addition. Although the precipitation of platelets of Mg17Al12 within α-Mg matrix was not significantly affected by the silver, mechanical properties such as hardness and tensile properties were improved with increasing Ag contents.

scholarly journals Research on energy efficient kinetics of drying raw material

2020 ◽  
Vol 216 ◽  
pp. 01093
Author(s):  
Jasur Safarov ◽  
Akhtam Khujakulov ◽  
Shakhnoza Sultanova ◽  
Ulugbek Khujakulov ◽  
Sunil Verma
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Equation ◽  
Boundary Conditions ◽  
Energy Efficient ◽  
Least Squares Method ◽  
Moisture Diffusion ◽  
Raw Material ◽  
Special Program ◽  
Mathematical Expressions ◽  
Kinetics Of

In this work, at constant values of the process temperature, the kinetics of drying was considered through the Fick diffusion equation with the corresponding initial and boundary conditions. To describe the process with mathematical expressions, Fick’s equation, which expresses the value of moisture content, is reduced to a dimensionless formula. When accepting the boundary conditions of the first kind, the ratio of the moisture diffusion coefficient to the square of the determining size was determined by the least squares method using a special program with subroutines for solving partial differential equations with a sufficient number of exponents in the solution.

scholarly journals GENERATING ALBEDO BOUNDARY CONDITIONS FOR NODAL DIFFUSION CODES USING SERPENT 2

2021 ◽  
Vol 247 ◽  
pp. 04013
Author(s):  
Ville Valtavirta ◽  
Jaakko Kuopanportti ◽  
Antti Rintala
Keyword(s):  
Monte Carlo ◽  
Boundary Conditions ◽  
Density Dependence ◽  
Boron Content ◽  
Structural Materials ◽  
Clear Distinction ◽  
Monte Carlo Code ◽  
Generation Process ◽  
Water Density ◽  
Nodal Diffusion

We use the Serpent Monte Carlo code to produce total and partial albedo boundary conditions that can be used to model the Loviisa NPP VVER-440 core with the nodal neutronics tools of Fortum. The albedo generation process is described in detail. The dependence of the generated albedos on boron content and water density is investigated and a clear distinction is noted in water density dependence between regions containing mostly water and those containing mostly structural materials. The Serpent generated albedos are currently used in production calculations for modeling the Loviisa reactors at Fortum.

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